Gripper shuttle for weft threads in a loom

ABSTRACT

The gripper shuttle has a yoke of uniform thickness throughout to eliminate shoulder portions for abutting the housing. The front end or nose of the yoke forms a closure for the housing. The yoke can be made of steel and the housing of a tough impactresistant synthetic material. The yoke is secured by rivets or otherwise to the housing and an internal reinforcing wall is formed in the housing.

[ Dec. 10, 1974 1 GRIPPER SHUTTLE FOR WEFT THREADS 3,237,653 3/1966 Klein et a1. 139/125 3,741,258 6/1973 Svaty 139/125 IN A LOOM [75] Inventor: Erw'in Pfarrwaller, Winterthur,

Switzerland Primary Examiner-Henry S. Jaudon Assignee: Sulzer Brothers Ltd., Winterthur, Attorney or Firm-Kenyon & Kenyon Remy Carr & Chapm Switzerland 22 Filed: June 27,1973

21 Appl.No.:374,239

ABSTRACT The gripper shuttle has a yoke of uniform thickness [30] Foreign Application Priority Data throughout to eliminate shoulder portions for abutting the housing. The front end or nose of the yoke forms July 10, 1972 Switzerland....................... 10295/72 a closure for the housing. The yoke can be made of steel and the housing of a tough impact-resistant synthetic material. The yoke is secured by rivets or otherwise to the housing and an internal reinforcing wall is formed in the housing.

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References Cited UNITED STATES PATENTS 8 Claims, 10 Drawing Figures 2,660,201 11/1953 Darash............................... 139/125 GRIPPER SHUTTLE FOR WEFT THREADS IN A LOOM This'invention relates to a gripper shuttle for weft threads in a weaving machine.

As is known, various types of weaving machines which operate with weft thread supply spools located outside a weaving shed require the use of gripper shuttles in order to introduce the weft thread into the shed. Generally, these gripper shuttles are sized of standard dimensions of about 90 X 14 X 16 millimeters (mm) and weigh about 30 to 60 grams. The gripper shuttles are usually constructed of three parts, i.e. a U-shaped weft-thread clamp, a head part and a caselike housing that encloses the clamp.

The U-shaped weft-thread clamp generally has a pair of claim arms which carry clamp jaws at the free ends while the opposite ends are connected with one another by a yoke. In addition, the clamp arms have been elastically prestressed in order to press the jaws together. In order to open the clamp in operation, a wedge-shaped or cone-shaped clamp opener has been driven between the clamp arms at suitable places. When a weft-thread end is introduced between the opened clamp jaws, for example, by means of a similar clamp made as a thread-supplier, and the clamp-opener is retracted, the weft-thread clamp grips the thread for the next weft insert.

The head part normally consists of a massive metal part, made as a rule of steel. The front of the head part, as viewed in the direction of flight, has a sort of blunt rounded knife-edge which facilitates passage of the shuttle through guide teeth which usually form a shuttle path and entry into a shuttle brake at the shuttlecatching end of the path. The clamp yoke and the head part may be a single piece, as is known, or may be made of different materials and be connected together by electro-welding, by riveting, or in some other way. The head part is usually welded to the front end of the housing, or they are even made in one piece.

The housing of most of the known gripper shuttles consists of a flat smooth metal case of approximately rectangular or octagonal cross section which is open at the rear end. The housing has a slot in each of these wide side-walls to expose the clamp jaws and to allow entry of the weft-thread supplier when the weft-thread clamp is open, for the purpose of introducing the weftthread end between the spread-apart clamp jaws. A pair of oppositely disposed holes have also been formed in the wide side-walls at a spacing of about millimeters(mm) from the rear end of the housing through which the clamp-opener is introduced between the two clamp-arms to open the clamp. The front end of the housing is usually closed by the head-part of the clamp. As a rule, during the assembly of the shuttle, the clamp, with the yoke in front, is introduced into the housing from the rear and is welded to the housing, on occasion with the head part, or is secured in some other way.

duced from the front into the housing until the housing With one known form of construction, the front end of the housing and the clamp yoke are welded electronically and simultaneously, in one operation, to the head abuts against a stop provided for this purpose at the head part, whereupon the housing is riveted to the clamp-yoke. This synthetic-material shuttle, in comparison with the older all-metal shuttle, has substantial advantages. Because of the small weight, the shot speed, that is, the speed with which the weft thread is carried into the shed, is higher for the same shot energy. The good sliding characteristics of the synthetic substance, in comparison with steel or some other metal, permit the elimination, to a great extent, if not completely, of any need to lubricate. This eliminates any danger of a lubricant soiling the woven product. The center of gravity of this shuttle is definitely more forward in the direction of the shot. This head-loading improves the behavior of the shuttle during passage through the guide-teeth of the path.

With modern weaving machines, a shot speed of the order of some 30 meters per second and a shot sequence of more than 300 shots per minute are reached. Shots therefore have to be accelerated within a few thousands of a second to their top speed, and have to be braked at the shuttle-catching end in a shuttlebrake. In spite of the small weight of the shuttle, this requires great forces. The life of the shuttle some millions of shots is thus a limited life, disregarding derangements that may result from breakage of the weftthread clamp or some other derangement of the housing which may occur in the course of time such as deformations impairing correct flight of the shuttle.

In order to increase shuttle life, it has been proposed to position or form a bridge-like reinforcing wall in the interior of the shuttle, at least over a part of the shuttle length. Through this, the housing is stiffened and strengthened, and is much better able to endure the stresses that occur during operation, particularly those of the braking process.

In one case, a stop has been provided at the head part of the clamp against which the front end of the housing fits to make the transition between the surface of the headpiece merge smoothly and flush with the surface of the housing. However, this stop creates some difiiculties in the production of the shuttle and makes additional operations necessary in the assembly of the yoke and head-part.

Accordingly, it is as object of the invention to reduce the total weight of a gripper shuttle.

It is another object of the invention to provide a gripper shuttle particularly suited to a high speed weaving machine.

Briefly, the invention provides a clamp for a gripper shuttle which has a yoke of continuously smooth outer profile. In addition, the yoke has a front end which forms a closure for an opening in a front end of a housing of the shuttle. In this way, the clamp can be made in a relatively simple manner and with a smooth uni form profile from a steel strip. A thickening of the yoke and a stop on the housing are eliminated. The front end of the yoke extends out of the housing and forms a head part of the shuttle which, during flight along a shuttle path remains out of contact with the guide teeth defining the path.

Because of this, and above all, when use is made of a synthetic-substance housing, the danger of undesirable vibrations of the clamp arms during the flight of the shuttle is diminished. The connection between the yoke and housing can be carried out in any known way, for example by riveting, by screws, or by an adhesive. In order to improve the connection, the yoke may have recesses in which the means used for fastening engage.

thickening in the head part, the decrease of weight is more pronounced in comparison with the known constructions with the result that the gripper-shuttle is particularly suitable for high-speed machines.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a top view of a gripper shuttle according to the invention;

FIG. 2 illustrates a view of a narrow side of the shuttle;

FIGS. 3, 4 and 5 each illustrate views taken along lines III/III, IV/IV and V/V, respectively, of FIG. 1;

FIG. 6 illustrates a view of the weft-thread clamp of FIG. 1 in the same position as shown in FIG. 1;

FIG. 7 illustrates a view of a modified shuttle according to the invention;

FIG. 8 illustrates a side view of the shuttle of FIG. 7;

FIG. 9 illustrates a view of another modified shuttle according to the invention; and

FIG. 10 illustrates a side view of the shuttle of FIG. 9. Similar reference characters are used throughout to indicate like parts in the Figures of the drawings.

Referring to FIGS. 1, 2 and 6, a weft thread clamp has two spring clamp arms 1, 1' which carry clamp jaws 2, 2 at the end and which by their spring force at the free rear ends, viewed in the direction of flight of the shuttle, press the clamp-jaws 2, 2' against one another to hold an end 3 of a weft-thread clamped. The front ends of the clamp-arms 1, 1, are firmly connected together by a yoke 4. This yoke 4 has cut-outs 5, 5 for the attachment of a caselike housing 6, for example, by

, the aid of rivets 7, 7 (FIG. 5), which pass through cut- .outs 5, 5. The front end 8 of the yoke 4 forms the closure of the opening at the front end 9 of the housing 6 and extends beyond the housing 6. To this end, as shown, the front end 8 is of a cross-section equal to the size of the opening of the housing 6.

The yoke has a uniform outer profile along the entire length. This profile is smaller, by the thickness of the housing 6, than the profile of the complete shuttle. Thus, direct contact of the shuttle clamp with the guide-teeth of the shuttle-path is avoided. If the housing, as in this form of construction, consists of a tough impact-resistant and vibration-damping synthetic material, then a danger of undesirable vibrations of the clamp-arms is practically completely eliminated.

At the rear open end, the wide side walls 10, 10' forming the top and bottom side walls of the housing 6 have slotted cut-outs 11, 11' into which a threadsupplier (not shown) brings the end 3 of the weft thread while the clamp-jaws 2, 2' are open, for the purpose of passing the thread to the shuttle clamp. The housing 16 is provided with two holes 12, 12 at some spacing from the rear end, through which a wedgeshape or cone-shape clamp opener (not shown) can be thrust for the purpose of spreading apart the two clamp-arms 1, 1, and opening the clamp.

Referring to FIGS. 1 and 3, thickenings of hard-metal inserts 13, 13', are provided at those places where the clamp-opener contacts the arms, for the purpose of avoiding premature wear of the clamp arms 1, 1'. Another pair of thickenings 14, 14' are also disposed in the region of the cut-out 11, and serve the gripping-end clamp-opener of the weaving machine after entry of the weft-thread is completed.

The interior of the shuttle body 6 is formed with a bridge-like internal longitudinal support wall for stiffening and strengthening the housing 6. This support wall consists of two parts 15, 15a between the wide side-walls 10, 10' and situated opposite one another to both sides of the clamp along the entire length of the free space between the two clamp arms 1, 1. The support wall 15, 15a leaves a sufiicient clearance on both sides to permit pushing in of the clamp, in an open state, from the front end during assembly of the shuttle without impairing unobstructed movement of the clamp arms during operation. The housing 6 itself has the form of a smooth profiled tube, such as can be produced through extrusion, casting (preferably as a pressure casting), drawing, or in some other suitable way, and made either of metal or of some synthetic substance. The bridge-like support-wall 15, 15a may thus be made during the production of the tube and simultaneously with the case, or else the support wall may be put in later, and be riveted, stuck, or bonded or otherwise secured to the side-walls 10, 10'. The rear open end of the housing 6, at the place where the impacter of the shooting mechanism encounters the housing end at the shooting of the shuttle for the insertion of the weft is provided with flange-like reinforcements 16, 16' of a known type, which partly close the rear opening of the housing outside the region of the cutouts ll, 11.

Referring to FIGS. 1, 4 and 6, the clamp arms 1, 1' may have a third pair of thickenings 21, 21' which form a limitation of the closing movement of the arms 1, 1, in that these thickenings 21, 21 encounter the supportwall 15, and in a known manner improve the position of the clamp and housing relative to one another. These thickenings 21, 21 also represent an additional ensurance against vibration of the clamp arms 1, l.

The front end of the clamp yoke can have any desired form provided that, in accordance with the characteristics of the invention, there are no thickenings and offsets. Thus, as shown in FIGS. 7 and 8, the front end 8 of the yoke 4 is made as a curved-shape or wedge-shape cutting edge, whose surface merges into that of the corresponding tapered-down front edge 9 of the housing 6 As shown in FIGS. 9 and 10, the front ends 8, 9 of the yoke 4 and housing 6, respectively, are rounded off in common, and their surfacesmerge flush with one another.

What is claimed is:

1. A gripper shuttle comprising a caselike housing having an opening in a front end thereof; and

a thread clamp mounted in said housing, said clamp having a'pair of clamp arms within said housing and a yoke connecting said arms together, said yoke having a continuously smooth outer profile and a front end forming a closure for said opening in said front end of said housing, said front end of said yoke being of a cross-section equal to the size of said opening.

2. A gripper shuttle as set forth in claim 1 wherein said yoke extends outwardly beyond said front end of said housing.

3. A gripper shuttle as set forth in claim 1 wherein said yoke includes at least one cut-out and said shuttle includes a rivet passing through said cut-out to secure said yoke and housing together.

4. A gripper forming top'and bottom side walls and shuttle as set forth in claim 1 wherein said housing has a pair of wide side walls, a bridge-like internal longitudinal support wall between said side walls in the space between said clamp arms for stiffening and strengthening said housing.

5. A gripper shuttle as set forth in claim 1 wherein said housing is made of tough impact resistant synthetic material and said clamp is made of steel.

6. A gripper shuttle as set forth in claim 1 wherein said thread clamp has a smooth uniform profile.

7. A gripper shuttle as set forth in claim 1 wherein said yoke extends outwardly beyond said front end of said housing and said front end is of a curved shape and wherein said housing has a tapered down front edge merging into a surface of said front end of said yoke.

8. A gripper shuttle as set forth in claim 1 wherein said yoke has a rounded front end and said housing has a rounded front end with respective surfaces on each merging in flush relationship with each other.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,853,152 Dated December 10, 197

lnventofls) Erwin Pfarrwaller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, between line 50 and 51, insert the following:

--It is anotherobject of the invention to eliminate shoulders. in a yoke of a gripper shuttle.

Columo 4, line "16" should be --6--.

Signed and sealed this 4th day of March 1975.

(SEAL) Attest:

' c MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks USCOMM'DC BO376-P69 FORM Po-1o50 (10-69) v UvS. GOVERNMENT PRINTING OFFICE I! 0-366434. 

1. A gripper shuttle comprising a caselike housing having an opening in a front end thereof; and a thread clamp mounted in said housing, said clamp having a pair of clamp arms within said housing and a yoke connecting said arms together, said yoke having a continuously smooth outer profile and a front end forming a closure for said opening in said front end of said housing, said front end of said yoke being of a cross-section equal to the size of said opening.
 2. A gripper shuttle as set forth in claim 1 wherein said yoke extends outwardly beyond said front end of said housing.
 3. A gripper shuttle as set forth in claim 1 wherein said yoke includes at least one cut-out and said shuttle includes a rivet passing through said cut-out to secure said yoke and housing together.
 4. A gripper forming top and bottom side walls and shuttle as set forth in claim 1 wherein said housing has a pair of wide side walls, a bridge-like internal longitudinal support wall between said side walls in the space between said clamp arms for stiffening and strengthening said housing.
 5. A gripper shuttle as set forth in claim 1 wherein said housing is made of tough impact resistant synthetic material and said clamp is made of steel.
 6. A gripper shuttle as set forth in claim 1 wherein said thread clamp has a smooth uniform profile.
 7. A gripper shuttle as set forth in claim 1 wherein said yoke extends outwardly beyond said front end of sAid housing and said front end is of a curved shape and wherein said housing has a tapered down front edge merging into a surface of said front end of said yoke.
 8. A gripper shuttle as set forth in claim 1 wherein said yoke has a rounded front end and said housing has a rounded front end with respective surfaces on each merging in flush relationship with each other. 